This invention relates generally to drive devices, and more particularly, to a mechanism for sensing the direction of rotation of elements within or related to a drive device. This invention may be used with a variety of drive devices including without limitation hydrostatic transmissions, which also come in a variety of configurations, including parallel pump and motor, dual pump and motor, and configurations where the hydrostatic transmission is incorporated within a housing containing gearing, often known as an integrated hydrostatic transaxle or IHT.